I recently assembled a Printrbot Jr. and was able to connect to Repetier, and when I tried to manually control the bot it gave me the error, Printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting).

But when I send the bot home it will return home so I know the axes motors are working.

Printrbot connects to pc but will only goto home position

In Repetier-host you should be able to check the log (drag the top of the logging area up if it's not visible.) For displayed errors.

You should be able to find a fan extension cable at many computer stores; I got one from Amazon. A 2 wire cable is best, but a 3 site will work fine - just let the extra pin hang off the side, and make sure you use the same two sides on both ends.

Have you gotten anywhere with this? After upgrading my firmware on my Rev D. Printrbot Plus V1, I get the same behavior if I attach the Extrudrboard. It will home the axis, but anything else results in:

Printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)>>>m999SENDING:M999Resend: 1Error:2: Extruder switched off. MINTEMP triggered !Error:Printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)

There is nothing in the pronterface.exe.log, here's Repetier-Hosts log output: